This summer, night after night, the lanky 14-year-old texted with friends for hours on end, sometimes not going to sleep until well after the sun was up. She’d interrupt her evening showers to check for messages, and at night she’d lie in bed with her phone pressed against her thigh to make sure she’d be alerted to any new messages.

The Metuchen High School honors student sends and receives up to 10,000 text messages a month. That means if she was sending and receiving messages 24 hours a day, seven days a week — which she’s not — she’d still send and receive more than 13 texts every hour.

In addition to well-publicized problems of texting while driving, doctors have found another serious health risk — lack of sleep — is disrupting teenagers’ lives. The doctors see teen text-messaging at night as a dangerous trend that can lead to poor performance in school.

"They’re not able to perform in class or in sports," said R. Michael Seyffert of the New Jersey Neuroscience Institute at JFK Medical Center in Edison. Seyffert works with many teenagers who have trouble sleeping. "That tiredness, that fatigue, has profound effects on being able to function throughout the day."

While Jackie may be an extreme case, she isn’t alone. According to a recent Nielsen study, 13- to 17-year-olds send or receive an average of 1,742 text messages a month — more than seven times the average number of calls they place on their cell phones.

"When I put it away or turn it off, I’m very anxious," Jackie said. "You know there are people trying to text you, you know they’re trying to get in contact with you. You feel bad that you’re not answering because they are used to you always answering."

Seyffert, who calls the night-texting problem a "crisis," said he sees two to three teenagers a month with severe texting issues, something he defines as two or more hours of texting and phoning each night. He said texting at night is a trend he has noticed a lot in the last five years, and surmised that the situation will only get worse.

Alexander Pais/For The Star-Ledger Lynn Warner and Sue Warner listen as Sue's daughter Jackie Ferrara, 14, talks about her lack of sleep at JFK Medical Center in Edison on Friday. Doctors are becoming concerned with 'night-texting' with teenagers, who are losing hours of sleep because of late night messaging with friends.

'A WHOLE DIFFERENT WORLD'

Janet Wojcik of Metuchen said texting is a way of life for her 19-year-old son, Devin, and 15-year-old daughter, Simone.

"Sometimes you’ll walk upstairs at 2 or 3 a.m. and see the glow of the phone because they’re texting," said Wojcik, 45. "It’s a whole different world."

Wojcik said her kids oftentimes don’t know what to do with themselves when their gadgets run out of charge or batteries. She said, instead of relying on technology, kids should interact face-to-face.

"They’re spending all their free time with technology-related items, whether it’s their cell phone, iPod or video games," she said. "I personally believe they should be doing more like sports, being outdoors and reading."

Wojcik began taking her daughter’s cell phone away at 9 p.m. on school nights so she could get enough sleep. But last Sunday, Simone had already sent 422 messages and received 655 by evening. Even though her phone has been taken away at night, she still wakes up wanting to see if she has missed messages. During the summer, she would send messages while she was half-asleep.

"I would be falling asleep but still try to answer my texts," Simone said. "But my eyes were closed, so I’d send random messages that didn’t make any sense. I’d realize it the next morning."

Some teens, like Jackie, who just started her freshman year, have begun to see doctors like Seyffert because of intense migraines, a symptom of lack of sleep.

Since school started, Jackie’s cut back on pulling texting all-nighters, but still doesn’t go to bed until 2 or 3 a.m., and still wakes at times to see if she has any messages. She said the lack of sleep is starting to take its toll at school.

"The first two periods I’m basically a ghost walking," Jackie said. "I’m just kind of there, but not mentally there. I definitely think it’s a problem for kids my age, maybe not all of them, but a lot of my friends text until at least 3 a.m. It’s just kind of crazy how we can always stay up and keep going with normal life."

Alexander Pais/For The Star-LedgerMichael Seyffert, associate professor of child neurology is seeing lots of young people who have problems sleeping at JFK Medical Center in Edison. Doctors are becoming concerned with 'night-texting' with teenagers, who are losing hours of sleep because of late night messaging with friends.

LONG TERM HEALTH EFFECTS

The consequences, Seyffert said, can be detrimental.

"People who get less sleep, they act like they’ve been drinking alcohol," he said. "There’s impairment in judgment and reaction time. These are kids that need to be their best in terms of their school work and learning new skills, like driving. You wouldn’t let your child drive drunk, why would you let your child, an older teenager, get in a car (if he’s) been texting all night?"

Jackie’s mother and father said they did not want to take away her phone because they don’t want to treat her as a small child. They said they’d rather Jackie learn to prioritize.

"She’s complying with every other rule that I have in the house," said Sue Warner, Jackie’s mother. "She’s getting honors grades, she’s doing well in sports, and she does chores in the house … the only thing she’s not doing is sleeping enough."

Videotapes from tests done at JFK Medical Center’s sleep center show several patients getting up in the middle of the night to send text messages. In one case, a nurse asked a teenage patient if his cell phone was off. He answered ‘yes,’ but is then seen texting several times during the night.

Sudhansu Chokroverty, the center’s clinical neurophysiology program director, said no studies have been published in the United States on night texting, but a Belgian study published in August found that late-night texting is affecting the sleep cycles of 44 percent of that country’s 16-year-olds. It revealed that 21 percent woke up one-to three-times a month to answer a text message. It also said it’s a weekly occurrence for 11 percent of the teens, and a nightly or every-other-night wake-up call for 12 percent.

"Sleep deprivation is a serious matter that can cause adverse consequences like obesity (and) Type II diabetes," Chokroverty said. "There are also long-term consequences, like increased heart disease, hypertension, memory impairment … It’s a serious thing, and of course it impacts the quality of life."

Jackie’s mother said she doesn’t think her daughter’s problem is limited to texting — Jackie’s addicted to all forms of communication. If she wasn’t sending messages, she’d be on her computer, or watching television, Warner said.

"With all of the media available to kids now, it gives them the opportunity to communicate on so many different levels," Warner said.

Seyffert said the answer to the problem is simple.

"Throw the phones away, turn the computers off, get the televisions out of the room, and let our kids sleep," he said.